1208.0575 (Iriya Muneta et al.)

Anomalous Fermi level behavior in GaMnAs at the onset of ferromagnetism    [PDF]

Iriya Muneta, Hiroshi Terada, Shinobu Ohya, Masaaki Tanaka

We present the first systematic study of the resonant tunneling spectroscopy on a series of ferromagnetic-semiconductor Ga1-xMnxAs with the Mn content x from ~0.01 to 3.2%. The Fermi level of Ga1-xMnxAs exists in the band gap in the whole x region. The Fermi level is closest to the valence band (VB) at x=1.0% corresponding to the onset of ferromagnetism near the metal-insulator transition (MIT), but it moves away from the VB with increasing or decreasing x from 1.0%. This anomalous behavior of the Fermi level indicates that the ferromagnetism and MIT emerge in the Mn-derived impurity band.

View original: http://arxiv.org/abs/1208.0575